limits of a reprap printer

Hello,

Since I am planning on building a reprap printer, I was wondering what the limits are for the machine? I know that the max dimensions for a reprap design were 300x300x100mm, but what about the following things:

Minimum for:
- a sphere
- a cone
- a cube
- a supported sphere with a cone
- a hole

I was wondering this because if I want to make something like a pawn chess piece, i dont want to see if flattened out because of gravity...

- A sphere - it looks like it could happen soon, but honestly it's not there yet - the overhang is too much. The rule of thumb is not to go over 45 degrees overhang.
- A cone - no problem, as long as the base is down. An inverted cone, not so much.
- A cube - again, as long as one side is down, no problem.
- A supported sphere with a cone - ?? If I understand this properly, it can't do it yet.
- A hole - horizontal holes are generally teardrop, vertical holes are fine. if you don't need the hole to hold something, it doesn't necessarily have to be teardrop but it won't be perfectly circular.. if you really need a perfectly circular hole, you'll want to put a pilot hole in the model and drill it out.. the teardrop shape works well for holding rods and screws, though.

I was able to print a fairly decent sphere recently: [blog.reprap.org]

I also tried a more complex shape, with limited success: [forums.reprap.org]

In theory, you could use the same technique to do other overhangs. A chess pawn shouldn't be too bad.

As for the actual build volume, it's probably closer to 200x200x90 on my machine, once you take into account the size of the carriage and the depth of the extruder.

I got a lot of good things to think about when I saw the message of DeGroof. I hope I can draw some 3d things while waiting, but its a bit hard in school with the new drawing programs they're using...

I am pretty sure that I can make some nice reprap chess pieces for you guys. At this moment I got a small game pawn, but building the support is giving me a hard time. See the attachments for the file. Anything that I have to change (besides using less support material)?